Chapter 7: Membrane Structure and Function

Question 1

Amphipathic

Answer 1

Both hydrophobic and hydrophilic regions

Question 2

Fluid mosaic model

Answer 2

Presents membrane as mosaic of protein molecules floating in a fluid bilayer of phospholipids

Question 3

Peripheral proteins

Answer 3

Proteins bound to the surface of the membrane

Question 4

Integral proteins

Answer 4

Proteins that penetrate the hydrophobic core

Question 5

Transmembrane proteins

Answer 5

Integral proteins that span the membrane

Question 6

Glycolipids

Answer 6

Carbohydrates bonded to lipids

Question 7

Glycoproteins

Answer 7

Carbohydrates bonded to proteins

Question 8

Selective permeability

Answer 8

Some substances cross more easily than others

Question 9

Transport proteins

Answer 9

Channel proteins, carrier proteins

Question 10

Diffusion

Answer 10

Movement of particles of any substance so that they spread out even,y into available space; high —-> low concentration

Question 11

Concentration gradient

Answer 11

The region along which the density of a chemical substance increases or decreases

Question 12

Passive transport

Answer 12

Diffusion of a substance, no energy is required

Question 13

Osmosis

Answer 13

Diffusion of free water (water molecules not clustered around another substance) across a selectively permeable membrane

Question 14

Tonicity

Answer 14

Ability of a surrounding solution to cause a cell to gain or lose water

Question 15

Isotonic

Answer 15

Equal water and solute concentrations on either side of the membrane

Question 16

Hypertonic

Answer 16

Solute concentration is higher (water concentration lower) on one side of the membrane (cell crenates/raisins)

Question 17

Hypotonic

Answer 17

Solute concentration is lower (water concentration higher) on one side of the membrane (cell explodes/lyses)

Question 18

Osmoregulation

Answer 18

Control of solute concentration and water balance

Question 19

Facilitated diffusion

Answer 19

Transport proteins speed the passive movement of molecules across the plasma membrane

Question 20

Channel proteins

Answer 20

Hydrophilic channel that certain molecules or ions can use as a tunnel

Question 21

Carrier proteins

Answer 21

Bind to molecules and change shape to shuttle them across the membrane

Question 22

Active transport

Answer 22

Movement of material up the concentration gradient from low concentration to a high concentration

Question 23

Sodium-potassium pump

Answer 23

Energizes the transport of K into the cell and Na out of the cell

Question 24

Electrogenic pump

Answer 24

Transport protein that generates voltage across a membrane

Question 25

Proton pump

Answer 25

Actively transports hydrogen ions out of the cell

Question 26

Cotransport

Answer 26

Active transport of a solute indirectly allows diffusion of another substance

Question 27

Exocytosis

Answer 27

Materials packaged into vesicles migrate to membrane, fuse with it, and release contents outside the cell

Question 28

Endocytosis

Answer 28

Macromolecules are taken into the cell in vesicles; phagocytosis, pinocytosis, receptor-mediated endocytosis

Question 29

Phagocytosis

Answer 29

Cell eats a particle by packing it into a food vacuole, fuses with a lysosome, and digests it

Question 30

Pinocytosis

Answer 30

Molecules taken up when extracellular fluid is “gulped” into tiny vesicles

Question 31

Receptor-mediated endocytosis

Answer 31

Vesicle formation is triggered by solute binding to receptors